If you've ever questioned the claims made by big cellular network operators like "America's fastest network", then here's an article just for you. After driving more than 20,000 miles and surveying mobile data speeds across the U.S, PCMag's data shows AT&T has the fastest overall cellular data network while Verizon's proved the most reliable.

Meanwhile, T-Mobile's 4G LTE network received solid marks for speed and reliability, although it continues to be marred by its very limited (but growing) availability. T-Mo's HSPA+ network though (where LTE isn't available) casts a relatively wide net across the states. The carrier's non-LTE offering actually out-maneuvered all other 3G networks when it came to sustained download speeds; however, that same network kept testers waiting when it came to HTTP responses giving AT&T a palpable edge during some scenarios.

Like T-Mo, Sprint's LTE network is also a work in progress. Unfortunately though, Sprint couldn't keep up with its three biggest competitors in most respects. Even so, Sprint's LTE network was an improvement over PCMag's results from last year, but still managed to lag behind AT&T, Verizon and T-Mobile wherever those carriers had 4G LTE options.

"As I spoke to the carriers before starting Fastest Mobile Networks 2013, they agreed that they were all aiming for at least a consistent 8/4 [8Mbps down, 4Mbps up] experience across their LTE networks." wrote PCMag's Sascha Sagan. "They're far from it. AT&T failed to deliver 8 megabits down at least 20 percent of the time in two thirds of our cities. Verizon did even worse; it only delivered 8Mbps results 80% of the time in Detroit and Indianapolis. And Sprint's hometown of Kansas City was the only place where we saw Sprint LTE exceeding 8Mbps more than half the time."